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59ae38984f
libpng/contrib/libtests/pngstest.c
John Bowler 59ae38984f [libpng16] Corrected simplified API default gamma for color-mapped output, added 
a flag to change default. In 1.6.0 when the simplified API was used
to produce color-mapped output from an input image with no gamma
information the gamma assumed for the input could be different from
that assumed for non-color-mapped output.  In particular 16-bit depth
input files were assumed to be sRGB encoded, whereas in the 'direct'
case they were assumed to have linear data.  This was an error.  The
fix makes the simplified API treat all input files the same way and
adds a new flag to the png_image::flags member to allow the
application/user to specify that 16-bit files contain sRGB data
rather than the default linear.
Fixed bugs in the pngpixel and makepng test programs.
2013-03-06 22:15:25 -06:00

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/*-
* pngstest.c
*
* Copyright (c) 2013 John Cunningham Bowler
*
* Last changed in libpng 1.6.1 [(PENDING RELEASE)]
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*
* Test for the PNG 'simplified' APIs.
*/
#define _ISOC90_SOURCE 1
#define MALLOC_CHECK_ 2/*glibc facility: turn on debugging*/
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <math.h>
#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
# include <config.h>
#endif
/* Define the following to use this test against your installed libpng, rather
* than the one being built here:
*/
#ifdef PNG_FREESTANDING_TESTS
# include <png.h>
#else
# include "../../png.h"
#endif
#ifdef PNG_SIMPLIFIED_READ_SUPPORTED /* Else nothing can be done */
#include "../tools/sRGB.h"
/* KNOWN ISSUES
*
* These defines switch on alternate algorithms for format conversions to match
* the current libpng implementation; they are set to allow pngstest to pass
* even though libpng is producing answers that are not as correct as they
* should be.
*/
#define ALLOW_UNUSED_GPC 0
/* If true include unused static GPC functions and declare an external array
* of them to hide the fact that they are unused. This is for development
* use while testing the correct function to use to take into account libpng
* misbehavior, such as using a simple power law to correct sRGB to linear.
*/
/* The following is to support direct compilation of this file as C++ */
#ifdef __cplusplus
# define voidcast(type, value) static_cast<type>(value)
# define aligncastconst(type, value) \
static_cast<type>(static_cast<const void*>(value))
#else
# define voidcast(type, value) (value)
# define aligncastconst(type, value) ((const void*)(value))
#endif /* __cplusplus */
/* During parallel runs of pngstest each temporary file needs a unique name,
* this is used to permit uniqueness using a command line argument which can be
* up to 22 characters long.
*/
static char tmpf[23] = "TMP";
/* Generate random bytes. This uses a boring repeatable algorithm and it
* is implemented here so that it gives the same set of numbers on every
* architecture. It's a linear congruential generator (Knuth or Sedgewick
* "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
* Hill, "The Art of Electronics".
*/
static void
make_random_bytes(png_uint_32* seed, void* pv, size_t size)
{
png_uint_32 u0 = seed[0], u1 = seed[1];
png_bytep bytes = voidcast(png_bytep, pv);
/* There are thirty three bits, the next bit in the sequence is bit-33 XOR
* bit-20. The top 1 bit is in u1, the bottom 32 are in u0.
*/
size_t i;
for (i=0; i<size; ++i)
{
/* First generate 8 new bits then shift them in at the end. */
png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
u1 <<= 8;
u1 |= u0 >> 24;
u0 <<= 8;
u0 |= u;
*bytes++ = (png_byte)u;
}
seed[0] = u0;
seed[1] = u1;
}
static void
random_color(png_colorp color)
{
static png_uint_32 color_seed[2] = { 0x12345678, 0x9abcdef };
make_random_bytes(color_seed, color, sizeof *color);
}
/* Math support - neither Cygwin nor Visual Studio have C99 support and we need
* a predictable rounding function, so make one here:
*/
static double
closestinteger(double x)
{
return floor(x + .5);
}
/* Cast support: remove GCC whines. */
static png_byte
u8d(double d)
{
d = closestinteger(d);
return (png_byte)d;
}
static png_uint_16
u16d(double d)
{
d = closestinteger(d);
return (png_uint_16)d;
}
/* sRGB support: use exact calculations rounded to the nearest int, see the
* fesetround() call in main(). sRGB_to_d optimizes the 8 to 16-bit conversion.
*/
static double sRGB_to_d[256];
static double g22_to_d[256];
static void
init_sRGB_to_d(void)
{
int i;
sRGB_to_d[0] = 0;
for (i=1; i<255; ++i)
sRGB_to_d[i] = linear_from_sRGB(i/255.);
sRGB_to_d[255] = 1;
g22_to_d[0] = 0;
for (i=1; i<255; ++i)
g22_to_d[i] = pow(i/255., 1/.45455);
g22_to_d[255] = 1;
}
static png_byte
sRGB(double linear /*range 0.0 .. 1.0*/)
{
return u8d(255 * sRGB_from_linear(linear));
}
static png_byte
isRGB(int fixed_linear)
{
return sRGB(fixed_linear / 65535.);
}
#if 0 /* not used */
static png_byte
unpremultiply(int component, int alpha)
{
if (alpha <= component)
return 255; /* Arbitrary, but consistent with the libpng code */
else if (alpha >= 65535)
return isRGB(component);
else
return sRGB((double)component / alpha);
}
#endif
static png_uint_16
ilinear(int fixed_srgb)
{
return u16d(65535 * sRGB_to_d[fixed_srgb]);
}
static png_uint_16
ilineara(int fixed_srgb, int alpha)
{
return u16d((257 * alpha) * sRGB_to_d[fixed_srgb]);
}
static png_uint_16
ilinear_g22(int fixed_srgb)
{
return u16d(65535 * g22_to_d[fixed_srgb]);
}
#if ALLOW_UNUSED_GPC
static png_uint_16
ilineara_g22(int fixed_srgb, int alpha)
{
return u16d((257 * alpha) * g22_to_d[fixed_srgb]);
}
#endif
static double
YfromRGBint(int ir, int ig, int ib)
{
double r = ir;
double g = ig;
double b = ib;
return YfromRGB(r, g, b);
}
#if 0 /* unused */
/* The error that results from using a 2.2 power law in place of the correct
* sRGB transform, given an 8-bit value which might be either sRGB or power-law.
*/
static int
power_law_error8(int value)
{
if (value > 0 && value < 255)
{
double vd = value / 255.;
double e = fabs(
pow(sRGB_to_d[value], 1/2.2) - sRGB_from_linear(pow(vd, 2.2)));
/* Always allow an extra 1 here for rounding errors */
e = 1+floor(255 * e);
return (int)e;
}
return 0;
}
static int error_in_sRGB_roundtrip = 56; /* by experiment */
static int
power_law_error16(int value)
{
if (value > 0 && value < 65535)
{
/* Round trip the value through an 8-bit representation but using
* non-matching to/from conversions.
*/
double vd = value / 65535.;
double e = fabs(
pow(sRGB_from_linear(vd), 2.2) - linear_from_sRGB(pow(vd, 1/2.2)));
/* Always allow an extra 1 here for rounding errors */
e = error_in_sRGB_roundtrip+floor(65535 * e);
return (int)e;
}
return 0;
}
static int
compare_8bit(int v1, int v2, int error_limit, int multiple_algorithms)
{
int e = abs(v1-v2);
int ev1, ev2;
if (e <= error_limit)
return 1;
if (!multiple_algorithms)
return 0;
ev1 = power_law_error8(v1);
if (e <= ev1)
return 1;
ev2 = power_law_error8(v2);
if (e <= ev2)
return 1;
return 0;
}
static int
compare_16bit(int v1, int v2, int error_limit, int multiple_algorithms)
{
int e = abs(v1-v2);
int ev1, ev2;
if (e <= error_limit)
return 1;
/* "multiple_algorithms" in this case means that a color-map has been
* involved somewhere, so we can deduce that the values were forced to 8-bit
* (like the via_linear case for 8-bit.)
*/
if (!multiple_algorithms)
return 0;
ev1 = power_law_error16(v1);
if (e <= ev1)
return 1;
ev2 = power_law_error16(v2);
if (e <= ev2)
return 1;
return 0;
}
#endif /* unused */
#define READ_FILE 1 /* else memory */
#define USE_STDIO 2 /* else use file name */
#define STRICT 4 /* fail on warnings too */
#define VERBOSE 8
#define KEEP_TMPFILES 16 /* else delete temporary files */
#define KEEP_GOING 32
#define ACCUMULATE 64
#define FAST_WRITE 128
#define sRGB_16BIT 256
static void
print_opts(png_uint_32 opts)
{
if (opts & READ_FILE)
printf(" --file");
if (opts & USE_STDIO)
printf(" --stdio");
if (opts & STRICT)
printf(" --strict");
if (opts & VERBOSE)
printf(" --verbose");
if (opts & KEEP_TMPFILES)
printf(" --preserve");
if (opts & KEEP_GOING)
printf(" --keep-going");
if (opts & ACCUMULATE)
printf(" --accumulate");
if (!(opts & FAST_WRITE)) /* --fast is currently the default */
printf(" --slow");
if (opts & sRGB_16BIT)
printf(" --sRGB-16bit");
}
#define FORMAT_NO_CHANGE 0x80000000 /* additional flag */
/* A name table for all the formats - defines the format of the '+' arguments to
* pngstest.
*/
#define FORMAT_COUNT 64
#define FORMAT_MASK 0x3f
static PNG_CONST char * PNG_CONST format_names[FORMAT_COUNT] =
{
"sRGB-gray",
"sRGB-gray+alpha",
"sRGB-rgb",
"sRGB-rgb+alpha",
"linear-gray",
"linear-gray+alpha",
"linear-rgb",
"linear-rgb+alpha",
"color-mapped-sRGB-gray",
"color-mapped-sRGB-gray+alpha",
"color-mapped-sRGB-rgb",
"color-mapped-sRGB-rgb+alpha",
"color-mapped-linear-gray",
"color-mapped-linear-gray+alpha",
"color-mapped-linear-rgb",
"color-mapped-linear-rgb+alpha",
"sRGB-gray",
"sRGB-gray+alpha",
"sRGB-bgr",
"sRGB-bgr+alpha",
"linear-gray",
"linear-gray+alpha",
"linear-bgr",
"linear-bgr+alpha",
"color-mapped-sRGB-gray",
"color-mapped-sRGB-gray+alpha",
"color-mapped-sRGB-bgr",
"color-mapped-sRGB-bgr+alpha",
"color-mapped-linear-gray",
"color-mapped-linear-gray+alpha",
"color-mapped-linear-bgr",
"color-mapped-linear-bgr+alpha",
"sRGB-gray",
"alpha+sRGB-gray",
"sRGB-rgb",
"alpha+sRGB-rgb",
"linear-gray",
"alpha+linear-gray",
"linear-rgb",
"alpha+linear-rgb",
"color-mapped-sRGB-gray",
"color-mapped-alpha+sRGB-gray",
"color-mapped-sRGB-rgb",
"color-mapped-alpha+sRGB-rgb",
"color-mapped-linear-gray",
"color-mapped-alpha+linear-gray",
"color-mapped-linear-rgb",
"color-mapped-alpha+linear-rgb",
"sRGB-gray",
"alpha+sRGB-gray",
"sRGB-bgr",
"alpha+sRGB-bgr",
"linear-gray",
"alpha+linear-gray",
"linear-bgr",
"alpha+linear-bgr",
"color-mapped-sRGB-gray",
"color-mapped-alpha+sRGB-gray",
"color-mapped-sRGB-bgr",
"color-mapped-alpha+sRGB-bgr",
"color-mapped-linear-gray",
"color-mapped-alpha+linear-gray",
"color-mapped-linear-bgr",
"color-mapped-alpha+linear-bgr",
};
/* Decode an argument to a format number. */
static png_uint_32
formatof(const char *arg)
{
char *ep;
unsigned long format = strtoul(arg, &ep, 0);
if (ep > arg && *ep == 0 && format < FORMAT_COUNT)
return (png_uint_32)format;
else for (format=0; format < FORMAT_COUNT; ++format)
{
if (strcmp(format_names[format], arg) == 0)
return (png_uint_32)format;
}
fprintf(stderr, "pngstest: format name '%s' invalid\n", arg);
return FORMAT_COUNT;
}
/* Bitset/test functions for formats */
#define FORMAT_SET_COUNT (FORMAT_COUNT / 32)
typedef struct
{
png_uint_32 bits[FORMAT_SET_COUNT];
}
format_list;
static void format_init(format_list *pf)
{
int i;
for (i=0; i<FORMAT_SET_COUNT; ++i)
pf->bits[i] = 0; /* All off */
}
#if 0 /* currently unused */
static void format_clear(format_list *pf)
{
int i;
for (i=0; i<FORMAT_SET_COUNT; ++i)
pf->bits[i] = 0;
}
#endif
static int format_is_initial(format_list *pf)
{
int i;
for (i=0; i<FORMAT_SET_COUNT; ++i)
if (pf->bits[i] != 0)
return 0;
return 1;
}
static int format_set(format_list *pf, png_uint_32 format)
{
if (format < FORMAT_COUNT)
return pf->bits[format >> 5] |= ((png_uint_32)1) << (format & 31);
return 0;
}
#if 0 /* currently unused */
static int format_unset(format_list *pf, png_uint_32 format)
{
if (format < FORMAT_COUNT)
return pf->bits[format >> 5] &= ~((png_uint_32)1) << (format & 31);
return 0;
}
#endif
static int format_isset(format_list *pf, png_uint_32 format)
{
return format < FORMAT_COUNT &&
(pf->bits[format >> 5] & (((png_uint_32)1) << (format & 31))) != 0;
}
static void format_default(format_list *pf, int redundant)
{
if (redundant)
{
int i;
/* set everything, including flags that are pointless */
for (i=0; i<FORMAT_SET_COUNT; ++i)
pf->bits[i] = ~(png_uint_32)0;
}
else
{
png_uint_32 f;
for (f=0; f<FORMAT_COUNT; ++f)
{
/* Eliminate redundant settings. */
/* BGR is meaningless if no color: */
if ((f & PNG_FORMAT_FLAG_COLOR) == 0 && (f & PNG_FORMAT_FLAG_BGR) != 0)
continue;
/* AFIRST is meaningless if no alpha: */
if ((f & PNG_FORMAT_FLAG_ALPHA) == 0 &&
(f & PNG_FORMAT_FLAG_AFIRST) != 0)
continue;
format_set(pf, f);
}
}
}
/* THE Image STRUCTURE */
/* The super-class of a png_image, contains the decoded image plus the input
* data necessary to re-read the file with a different format.
*/
typedef struct
{
png_image image;
png_uint_32 opts;
const char *file_name;
int stride_extra;
FILE *input_file;
png_voidp input_memory;
png_size_t input_memory_size;
png_bytep buffer;
ptrdiff_t stride;
png_size_t bufsize;
png_size_t allocsize;
char tmpfile_name[32];
png_uint_16 colormap[256*4];
}
Image;
/* Initializer: also sets the permitted error limit for 16-bit operations. */
static void
newimage(Image *image)
{
memset(image, 0, sizeof *image);
}
/* Reset the image to be read again - only needs to rewind the FILE* at present.
*/
static void
resetimage(Image *image)
{
if (image->input_file != NULL)
rewind(image->input_file);
}
/* Free the image buffer; the buffer is re-used on a re-read, this is just for
* cleanup.
*/
static void
freebuffer(Image *image)
{
if (image->buffer) free(image->buffer);
image->buffer = NULL;
image->bufsize = 0;
image->allocsize = 0;
}
/* Delete function; cleans out all the allocated data and the temporary file in
* the image.
*/
static void
freeimage(Image *image)
{
freebuffer(image);
png_image_free(&image->image);
if (image->input_file != NULL)
{
fclose(image->input_file);
image->input_file = NULL;
}
if (image->input_memory != NULL)
{
free(image->input_memory);
image->input_memory = NULL;
image->input_memory_size = 0;
}
if (image->tmpfile_name[0] != 0 && (image->opts & KEEP_TMPFILES) == 0)
{
remove(image->tmpfile_name);
image->tmpfile_name[0] = 0;
}
}
/* This is actually a re-initializer; allows an image structure to be re-used by
* freeing everything that relates to an old image.
*/
static void initimage(Image *image, png_uint_32 opts, const char *file_name,
int stride_extra)
{
freeimage(image);
memset(&image->image, 0, sizeof image->image);
image->opts = opts;
image->file_name = file_name;
image->stride_extra = stride_extra;
}
/* Make sure the image buffer is big enough; allows re-use of the buffer if the
* image is re-read.
*/
#define BUFFER_INIT8 73
static void
allocbuffer(Image *image)
{
png_size_t size = PNG_IMAGE_BUFFER_SIZE(image->image, image->stride);
if (size+32 > image->bufsize)
{
freebuffer(image);
image->buffer = voidcast(png_bytep, malloc(size+32));
if (image->buffer == NULL)
{
fflush(stdout);
fprintf(stderr,
"simpletest: out of memory allocating %lu(+32) byte buffer\n",
(unsigned long)size);
exit(1);
}
image->bufsize = size+32;
}
memset(image->buffer, 95, image->bufsize);
memset(image->buffer+16, BUFFER_INIT8, size);
image->allocsize = size;
}
/* Make sure 16 bytes match the given byte. */
static int
check16(png_const_bytep bp, int b)
{
int i = 16;
do
if (*bp != b) return 1;
while (--i);
return 0;
}
/* Check for overwrite in the image buffer. */
static void
checkbuffer(Image *image, const char *arg)
{
if (check16(image->buffer, 95))
{
fflush(stdout);
fprintf(stderr, "%s: overwrite at start of image buffer\n", arg);
exit(1);
}
if (check16(image->buffer+16+image->allocsize, 95))
{
fflush(stdout);
fprintf(stderr, "%s: overwrite at end of image buffer\n", arg);
exit(1);
}
}
/* ERROR HANDLING */
/* Log a terminal error, also frees the libpng part of the image if necessary.
*/
static int
logerror(Image *image, const char *a1, const char *a2, const char *a3)
{
fflush(stdout);
if (image->image.warning_or_error)
fprintf(stderr, "%s%s%s: %s\n", a1, a2, a3, image->image.message);
else
fprintf(stderr, "%s%s%s\n", a1, a2, a3);
if (image->image.opaque != NULL)
{
fprintf(stderr, "%s: image opaque pointer non-NULL on error\n",
image->file_name);
png_image_free(&image->image);
}
return 0;
}
/* Log an error and close a file (just a utility to do both things in one
* function call.)
*/
static int
logclose(Image *image, FILE *f, const char *name, const char *operation)
{
int e = errno;
fclose(f);
return logerror(image, name, operation, strerror(e));
}
/* Make sure the png_image has been freed - validates that libpng is doing what
* the spec says and freeing the image.
*/
static int
checkopaque(Image *image)
{
if (image->image.opaque != NULL)
{
png_image_free(&image->image);
return logerror(image, image->file_name, ": opaque not NULL", "");
}
else if (image->image.warning_or_error != 0 && (image->opts & STRICT) != 0)
return logerror(image, image->file_name, " --strict", "");
else
return 1;
}
/* IMAGE COMPARISON/CHECKING */
/* Compare the pixels of two images, which should be the same but aren't. The
* images must have been checked for a size match.
*/
typedef struct
{
/* The components, for grayscale images the gray value is in 'g' and if alpha
* is not present 'a' is set to 255 or 65535 according to format.
*/
int r, g, b, a;
} Pixel;
typedef struct
{
/* The background as the original sRGB 8-bit value converted to the final
* integer format and as a double precision linear value in the range 0..1
* for with partially transparent pixels.
*/
int ir, ig, ib;
double dr, dg, db; /* linear r,g,b scaled to 0..1 */
} Background;
/* Basic image formats; control the data but not the layout thereof. */
#define BASE_FORMATS\
(PNG_FORMAT_FLAG_ALPHA|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_LINEAR)
/* Read a Pixel from a buffer. The code below stores the correct routine for
* the format in a function pointer, these are the routines:
*/
static void
gp_g8(Pixel *p, png_const_voidp pb)
{
png_const_bytep pp = voidcast(png_const_bytep, pb);
p->r = p->g = p->b = pp[0];
p->a = 255;
}
static void
gp_ga8(Pixel *p, png_const_voidp pb)
{
png_const_bytep pp = voidcast(png_const_bytep, pb);
p->r = p->g = p->b = pp[0];
p->a = pp[1];
}
static void
gp_ag8(Pixel *p, png_const_voidp pb)
{
png_const_bytep pp = voidcast(png_const_bytep, pb);
p->r = p->g = p->b = pp[1];
p->a = pp[0];
}
static void
gp_rgb8(Pixel *p, png_const_voidp pb)
{
png_const_bytep pp = voidcast(png_const_bytep, pb);
p->r = pp[0];
p->g = pp[1];
p->b = pp[2];
p->a = 255;
}
static void
gp_bgr8(Pixel *p, png_const_voidp pb)
{
png_const_bytep pp = voidcast(png_const_bytep, pb);
p->r = pp[2];
p->g = pp[1];
p->b = pp[0];
p->a = 255;
}
static void
gp_rgba8(Pixel *p, png_const_voidp pb)
{
png_const_bytep pp = voidcast(png_const_bytep, pb);
p->r = pp[0];
p->g = pp[1];
p->b = pp[2];
p->a = pp[3];
}
static void
gp_bgra8(Pixel *p, png_const_voidp pb)
{
png_const_bytep pp = voidcast(png_const_bytep, pb);
p->r = pp[2];
p->g = pp[1];
p->b = pp[0];
p->a = pp[3];
}
static void
gp_argb8(Pixel *p, png_const_voidp pb)
{
png_const_bytep pp = voidcast(png_const_bytep, pb);
p->r = pp[1];
p->g = pp[2];
p->b = pp[3];
p->a = pp[0];
}
static void
gp_abgr8(Pixel *p, png_const_voidp pb)
{
png_const_bytep pp = voidcast(png_const_bytep, pb);
p->r = pp[3];
p->g = pp[2];
p->b = pp[1];
p->a = pp[0];
}
static void
gp_g16(Pixel *p, png_const_voidp pb)
{
png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
p->r = p->g = p->b = pp[0];
p->a = 65535;
}
static void
gp_ga16(Pixel *p, png_const_voidp pb)
{
png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
p->r = p->g = p->b = pp[0];
p->a = pp[1];
}
static void
gp_ag16(Pixel *p, png_const_voidp pb)
{
png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
p->r = p->g = p->b = pp[1];
p->a = pp[0];
}
static void
gp_rgb16(Pixel *p, png_const_voidp pb)
{
png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
p->r = pp[0];
p->g = pp[1];
p->b = pp[2];
p->a = 65535;
}
static void
gp_bgr16(Pixel *p, png_const_voidp pb)
{
png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
p->r = pp[2];
p->g = pp[1];
p->b = pp[0];
p->a = 65535;
}
static void
gp_rgba16(Pixel *p, png_const_voidp pb)
{
png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
p->r = pp[0];
p->g = pp[1];
p->b = pp[2];
p->a = pp[3];
}
static void
gp_bgra16(Pixel *p, png_const_voidp pb)
{
png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
p->r = pp[2];
p->g = pp[1];
p->b = pp[0];
p->a = pp[3];
}
static void
gp_argb16(Pixel *p, png_const_voidp pb)
{
png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
p->r = pp[1];
p->g = pp[2];
p->b = pp[3];
p->a = pp[0];
}
static void
gp_abgr16(Pixel *p, png_const_voidp pb)
{
png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
p->r = pp[3];
p->g = pp[2];
p->b = pp[1];
p->a = pp[0];
}
/* Given a format, return the correct one of the above functions. */
static void (*
get_pixel(png_uint_32 format))(Pixel *p, png_const_voidp pb)
{
/* The color-map flag is irrelevant here - the caller of the function
* returned must either pass the buffer or, for a color-mapped image, the
* correct entry in the color-map.
*/
if (format & PNG_FORMAT_FLAG_LINEAR)
{
if (format & PNG_FORMAT_FLAG_COLOR)
{
if (format & PNG_FORMAT_FLAG_BGR)
{
if (format & PNG_FORMAT_FLAG_ALPHA)
{
if (format & PNG_FORMAT_FLAG_AFIRST)
return gp_abgr16;
else
return gp_bgra16;
}
else
return gp_bgr16;
}
else
{
if (format & PNG_FORMAT_FLAG_ALPHA)
{
if (format & PNG_FORMAT_FLAG_AFIRST)
return gp_argb16;
else
return gp_rgba16;
}
else
return gp_rgb16;
}
}
else
{
if (format & PNG_FORMAT_FLAG_ALPHA)
{
if (format & PNG_FORMAT_FLAG_AFIRST)
return gp_ag16;
else
return gp_ga16;
}
else
return gp_g16;
}
}
else
{
if (format & PNG_FORMAT_FLAG_COLOR)
{
if (format & PNG_FORMAT_FLAG_BGR)
{
if (format & PNG_FORMAT_FLAG_ALPHA)
{
if (format & PNG_FORMAT_FLAG_AFIRST)
return gp_abgr8;
else
return gp_bgra8;
}
else
return gp_bgr8;
}
else
{
if (format & PNG_FORMAT_FLAG_ALPHA)
{
if (format & PNG_FORMAT_FLAG_AFIRST)
return gp_argb8;
else
return gp_rgba8;
}
else
return gp_rgb8;
}
}
else
{
if (format & PNG_FORMAT_FLAG_ALPHA)
{
if (format & PNG_FORMAT_FLAG_AFIRST)
return gp_ag8;
else
return gp_ga8;
}
else
return gp_g8;
}
}
}
/* Convertion between pixel formats. The code above effectively eliminates the
* component ordering changes leaving three basic changes:
*
* 1) Remove an alpha channel by pre-multiplication or compositing on a
* background color. (Adding an alpha channel is a no-op.)
*
* 2) Remove color by mapping to grayscale. (Grayscale to color is a no-op.)
*
* 3) Convert between 8-bit and 16-bit components. (Both directtions are
* relevant.)
*
* This gives the following base format conversion matrix:
*
* OUT: ----- 8-bit ----- ----- 16-bit -----
* IN G GA RGB RGBA G GA RGB RGBA
* 8 G . . . . lin lin lin lin
* 8 GA bckg . bckc . pre' pre pre' pre
* 8 RGB g8 g8 . . glin glin lin lin
* 8 RGBA g8b g8 bckc . gpr' gpre pre' pre
* 16 G sRGB sRGB sRGB sRGB . . . .
* 16 GA b16g unpg b16c unpc A . A .
* 16 RGB sG sG sRGB sRGB g16 g16 . .
* 16 RGBA gb16 sGp cb16 sCp g16 g16' A .
*
* 8-bit to 8-bit:
* bckg: composite on gray background
* bckc: composite on color background
* g8: convert sRGB components to sRGB grayscale
* g8b: convert sRGB components to grayscale and composite on gray background
*
* 8-bit to 16-bit:
* lin: make sRGB components linear, alpha := 65535
* pre: make sRGB components linear and premultiply by alpha (scale alpha)
* pre': as 'pre' but alpha := 65535
* glin: make sRGB components linear, convert to grayscale, alpha := 65535
* gpre: make sRGB components grayscale and linear and premultiply by alpha
* gpr': as 'gpre' but alpha := 65535
*
* 16-bit to 8-bit:
* sRGB: convert linear components to sRGB, alpha := 255
* unpg: unpremultiply gray component and convert to sRGB (scale alpha)
* unpc: unpremultiply color components and convert to sRGB (scale alpha)
* b16g: composite linear onto gray background and convert the result to sRGB
* b16c: composite linear onto color background and convert the result to sRGB
* sG: convert linear RGB to sRGB grayscale
* sGp: unpremultiply RGB then convert to sRGB grayscale
* sCp: unpremultiply RGB then convert to sRGB
* gb16: composite linear onto background and convert to sRGB grayscale
* (order doesn't matter, the composite and grayscale operations permute)
* cb16: composite linear onto background and convert to sRGB
*
* 16-bit to 16-bit:
* A: set alpha to 65535
* g16: convert linear RGB to linear grayscale (alpha := 65535)
* g16': as 'g16' but alpha is unchanged
*/
/* Simple copy: */
static void
gpc_noop(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = in->r;
out->g = in->g;
out->b = in->b;
out->a = in->a;
}
#if ALLOW_UNUSED_GPC
static void
gpc_nop8(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->a == 0)
out->r = out->g = out->b = 255;
else
{
out->r = in->r;
out->g = in->g;
out->b = in->b;
}
out->a = in->a;
}
#endif
#if ALLOW_UNUSED_GPC
static void
gpc_nop6(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->a == 0)
out->r = out->g = out->b = 65535;
else
{
out->r = in->r;
out->g = in->g;
out->b = in->b;
}
out->a = in->a;
}
#endif
/* 8-bit to 8-bit conversions */
/* bckg: composite on gray background */
static void
gpc_bckg(Pixel *out, const Pixel *in, const Background *back)
{
if (in->a <= 0)
out->r = out->g = out->b = back->ig;
else if (in->a >= 255)
out->r = out->g = out->b = in->g;
else
{
double a = in->a / 255.;
out->r = out->g = out->b = sRGB(sRGB_to_d[in->g] * a + back->dg * (1-a));
}
out->a = 255;
}
/* bckc: composite on color background */
static void
gpc_bckc(Pixel *out, const Pixel *in, const Background *back)
{
if (in->a <= 0)
{
out->r = back->ir;
out->g = back->ig;
out->b = back->ib;
}
else if (in->a >= 255)
{
out->r = in->r;
out->g = in->g;
out->b = in->b;
}
else
{
double a = in->a / 255.;
out->r = sRGB(sRGB_to_d[in->r] * a + back->dr * (1-a));
out->g = sRGB(sRGB_to_d[in->g] * a + back->dg * (1-a));
out->b = sRGB(sRGB_to_d[in->b] * a + back->db * (1-a));
}
out->a = 255;
}
/* g8: convert sRGB components to sRGB grayscale */
static void
gpc_g8(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->r == in->g && in->g == in->b)
out->r = out->g = out->b = in->g;
else
out->r = out->g = out->b =
sRGB(YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
out->a = in->a;
}
/* g8b: convert sRGB components to grayscale and composite on gray background */
static void
gpc_g8b(Pixel *out, const Pixel *in, const Background *back)
{
if (in->a <= 0)
out->r = out->g = out->b = back->ig;
else if (in->a >= 255)
{
if (in->r == in->g && in->g == in->b)
out->r = out->g = out->b = in->g;
else
out->r = out->g = out->b = sRGB(YfromRGB(
sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
}
else
{
double a = in->a/255.;
out->r = out->g = out->b = sRGB(a * YfromRGB(sRGB_to_d[in->r],
sRGB_to_d[in->g], sRGB_to_d[in->b]) + back->dg * (1-a));
}
out->a = 255;
}
/* 8-bit to 16-bit conversions */
/* lin: make sRGB components linear, alpha := 65535 */
static void
gpc_lin(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = ilinear(in->r);
if (in->g == in->r)
{
out->g = out->r;
if (in->b == in->r)
out->b = out->r;
else
out->b = ilinear(in->b);
}
else
{
out->g = ilinear(in->g);
if (in->b == in->r)
out->b = out->r;
else if (in->b == in->g)
out->b = out->g;
else
out->b = ilinear(in->b);
}
out->a = 65535;
}
/* pre: make sRGB components linear and premultiply by alpha (scale alpha) */
static void
gpc_pre(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = ilineara(in->r, in->a);
if (in->g == in->r)
{
out->g = out->r;
if (in->b == in->r)
out->b = out->r;
else
out->b = ilineara(in->b, in->a);
}
else
{
out->g = ilineara(in->g, in->a);
if (in->b == in->r)
out->b = out->r;
else if (in->b == in->g)
out->b = out->g;
else
out->b = ilineara(in->b, in->a);
}
out->a = in->a * 257;
}
/* pre': as 'pre' but alpha := 65535 */
static void
gpc_preq(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = ilineara(in->r, in->a);
if (in->g == in->r)
{
out->g = out->r;
if (in->b == in->r)
out->b = out->r;
else
out->b = ilineara(in->b, in->a);
}
else
{
out->g = ilineara(in->g, in->a);
if (in->b == in->r)
out->b = out->r;
else if (in->b == in->g)
out->b = out->g;
else
out->b = ilineara(in->b, in->a);
}
out->a = 65535;
}
/* glin: make sRGB components linear, convert to grayscale, alpha := 65535 */
static void
gpc_glin(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->r == in->g && in->g == in->b)
out->r = out->g = out->b = ilinear(in->g);
else
out->r = out->g = out->b = u16d(65535 *
YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
out->a = 65535;
}
/* gpre: make sRGB components grayscale and linear and premultiply by alpha */
static void
gpc_gpre(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->r == in->g && in->g == in->b)
out->r = out->g = out->b = ilineara(in->g, in->a);
else
out->r = out->g = out->b = u16d(in->a * 257 *
YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
out->a = 257 * in->a;
}
/* gpr': as 'gpre' but alpha := 65535 */
static void
gpc_gprq(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->r == in->g && in->g == in->b)
out->r = out->g = out->b = ilineara(in->g, in->a);
else
out->r = out->g = out->b = u16d(in->a * 257 *
YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
out->a = 65535;
}
/* 8-bit to 16-bit conversions for gAMA 45455 encoded values */
/* Lin: make gAMA 45455 components linear, alpha := 65535 */
static void
gpc_Lin(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = ilinear_g22(in->r);
if (in->g == in->r)
{
out->g = out->r;
if (in->b == in->r)
out->b = out->r;
else
out->b = ilinear_g22(in->b);
}
else
{
out->g = ilinear_g22(in->g);
if (in->b == in->r)
out->b = out->r;
else if (in->b == in->g)
out->b = out->g;
else
out->b = ilinear_g22(in->b);
}
out->a = 65535;
}
#if ALLOW_UNUSED_GPC
/* Pre: make gAMA 45455 components linear and premultiply by alpha (scale alpha)
*/
static void
gpc_Pre(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = ilineara_g22(in->r, in->a);
if (in->g == in->r)
{
out->g = out->r;
if (in->b == in->r)
out->b = out->r;
else
out->b = ilineara_g22(in->b, in->a);
}
else
{
out->g = ilineara_g22(in->g, in->a);
if (in->b == in->r)
out->b = out->r;
else if (in->b == in->g)
out->b = out->g;
else
out->b = ilineara_g22(in->b, in->a);
}
out->a = in->a * 257;
}
#endif
#if ALLOW_UNUSED_GPC
/* Pre': as 'Pre' but alpha := 65535 */
static void
gpc_Preq(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = ilineara_g22(in->r, in->a);
if (in->g == in->r)
{
out->g = out->r;
if (in->b == in->r)
out->b = out->r;
else
out->b = ilineara_g22(in->b, in->a);
}
else
{
out->g = ilineara_g22(in->g, in->a);
if (in->b == in->r)
out->b = out->r;
else if (in->b == in->g)
out->b = out->g;
else
out->b = ilineara_g22(in->b, in->a);
}
out->a = 65535;
}
#endif
#if ALLOW_UNUSED_GPC
/* Glin: make gAMA 45455 components linear, convert to grayscale, alpha := 65535
*/
static void
gpc_Glin(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->r == in->g && in->g == in->b)
out->r = out->g = out->b = ilinear_g22(in->g);
else
out->r = out->g = out->b = u16d(65535 *
YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
out->a = 65535;
}
#endif
#if ALLOW_UNUSED_GPC
/* Gpre: make gAMA 45455 components grayscale and linear and premultiply by
* alpha.
*/
static void
gpc_Gpre(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->r == in->g && in->g == in->b)
out->r = out->g = out->b = ilineara_g22(in->g, in->a);
else
out->r = out->g = out->b = u16d(in->a * 257 *
YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
out->a = 257 * in->a;
}
#endif
#if ALLOW_UNUSED_GPC
/* Gpr': as 'Gpre' but alpha := 65535 */
static void
gpc_Gprq(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->r == in->g && in->g == in->b)
out->r = out->g = out->b = ilineara_g22(in->g, in->a);
else
out->r = out->g = out->b = u16d(in->a * 257 *
YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
out->a = 65535;
}
#endif
/* 16-bit to 8-bit conversions */
/* sRGB: convert linear components to sRGB, alpha := 255 */
static void
gpc_sRGB(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = isRGB(in->r);
if (in->g == in->r)
{
out->g = out->r;
if (in->b == in->r)
out->b = out->r;
else
out->b = isRGB(in->b);
}
else
{
out->g = isRGB(in->g);
if (in->b == in->r)
out->b = out->r;
else if (in->b == in->g)
out->b = out->g;
else
out->b = isRGB(in->b);
}
out->a = 255;
}
/* unpg: unpremultiply gray component and convert to sRGB (scale alpha) */
static void
gpc_unpg(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->a <= 128)
{
out->r = out->g = out->b = 255;
out->a = 0;
}
else
{
out->r = out->g = out->b = sRGB((double)in->g / in->a);
out->a = u8d(in->a / 257.);
}
}
/* unpc: unpremultiply color components and convert to sRGB (scale alpha) */
static void
gpc_unpc(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->a <= 128)
{
out->r = out->g = out->b = 255;
out->a = 0;
}
else
{
out->r = sRGB((double)in->r / in->a);
out->g = sRGB((double)in->g / in->a);
out->b = sRGB((double)in->b / in->a);
out->a = u8d(in->a / 257.);
}
}
/* b16g: composite linear onto gray background and convert the result to sRGB */
static void
gpc_b16g(Pixel *out, const Pixel *in, const Background *back)
{
if (in->a <= 0)
out->r = out->g = out->b = back->ig;
else
{
double a = in->a/65535.;
double a1 = 1-a;
a /= 65535;
out->r = out->g = out->b = sRGB(in->g * a + back->dg * a1);
}
out->a = 255;
}
/* b16c: composite linear onto color background and convert the result to sRGB*/
static void
gpc_b16c(Pixel *out, const Pixel *in, const Background *back)
{
if (in->a <= 0)
{
out->r = back->ir;
out->g = back->ig;
out->b = back->ib;
}
else
{
double a = in->a/65535.;
double a1 = 1-a;
a /= 65535;
out->r = sRGB(in->r * a + back->dr * a1);
out->g = sRGB(in->g * a + back->dg * a1);
out->b = sRGB(in->b * a + back->db * a1);
}
out->a = 255;
}
/* sG: convert linear RGB to sRGB grayscale */
static void
gpc_sG(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = out->g = out->b = sRGB(YfromRGBint(in->r, in->g, in->b)/65535);
out->a = 255;
}
/* sGp: unpremultiply RGB then convert to sRGB grayscale */
static void
gpc_sGp(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->a <= 128)
{
out->r = out->g = out->b = 255;
out->a = 0;
}
else
{
out->r = out->g = out->b = sRGB(YfromRGBint(in->r, in->g, in->b)/in->a);
out->a = u8d(in->a / 257.);
}
}
/* sCp: unpremultiply RGB then convert to sRGB */
static void
gpc_sCp(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
if (in->a <= 128)
{
out->r = out->g = out->b = 255;
out->a = 0;
}
else
{
out->r = sRGB((double)in->r / in->a);
out->g = sRGB((double)in->g / in->a);
out->b = sRGB((double)in->b / in->a);
out->a = u8d(in->a / 257.);
}
}
/* gb16: composite linear onto background and convert to sRGB grayscale */
/* (order doesn't matter, the composite and grayscale operations permute) */
static void
gpc_gb16(Pixel *out, const Pixel *in, const Background *back)
{
if (in->a <= 0)
out->r = out->g = out->b = back->ig;
else if (in->a >= 65535)
out->r = out->g = out->b = isRGB(in->g);
else
{
double a = in->a / 65535.;
double a1 = 1-a;
a /= 65535;
out->r = out->g = out->b = sRGB(in->g * a + back->dg * a1);
}
out->a = 255;
}
/* cb16: composite linear onto background and convert to sRGB */
static void
gpc_cb16(Pixel *out, const Pixel *in, const Background *back)
{
if (in->a <= 0)
{
out->r = back->ir;
out->g = back->ig;
out->b = back->ib;
}
else if (in->a >= 65535)
{
out->r = isRGB(in->r);
out->g = isRGB(in->g);
out->b = isRGB(in->b);
}
else
{
double a = in->a / 65535.;
double a1 = 1-a;
a /= 65535;
out->r = sRGB(in->r * a + back->dr * a1);
out->g = sRGB(in->g * a + back->dg * a1);
out->b = sRGB(in->b * a + back->db * a1);
}
out->a = 255;
}
/* 16-bit to 16-bit conversions */
/* A: set alpha to 65535 */
static void
gpc_A(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = in->r;
out->g = in->g;
out->b = in->b;
out->a = 65535;
}
/* g16: convert linear RGB to linear grayscale (alpha := 65535) */
static void
gpc_g16(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = out->g = out->b = u16d(YfromRGBint(in->r, in->g, in->b));
out->a = 65535;
}
/* g16': as 'g16' but alpha is unchanged */
static void
gpc_g16q(Pixel *out, const Pixel *in, const Background *back)
{
(void)back;
out->r = out->g = out->b = u16d(YfromRGBint(in->r, in->g, in->b));
out->a = in->a;
}
#if ALLOW_UNUSED_GPC
/* Unused functions (to hide them from GCC unused function warnings) */
void (* const gpc_unused[])
(Pixel *out, const Pixel *in, const Background *back) =
{
gpc_Pre, gpc_Preq, gpc_Glin, gpc_Gpre, gpc_Gprq, gpc_nop8, gpc_nop6
};
#endif
/* OUT: ----- 8-bit ----- ----- 16-bit -----
* IN G GA RGB RGBA G GA RGB RGBA
* 8 G . . . . lin lin lin lin
* 8 GA bckg . bckc . pre' pre pre' pre
* 8 RGB g8 g8 . . glin glin lin lin
* 8 RGBA g8b g8 bckc . gpr' gpre pre' pre
* 16 G sRGB sRGB sRGB sRGB . . . .
* 16 GA b16g unpg b16c unpc A . A .
* 16 RGB sG sG sRGB sRGB g16 g16 . .
* 16 RGBA gb16 sGp cb16 sCp g16 g16' A .
*
* The matrix is held in an array indexed thus:
*
* gpc_fn[out_format & BASE_FORMATS][in_format & BASE_FORMATS];
*/
/* This will produce a compile time error if the FORMAT_FLAG values don't
* match the above matrix!
*/
#if PNG_FORMAT_FLAG_ALPHA == 1 && PNG_FORMAT_FLAG_COLOR == 2 &&\
PNG_FORMAT_FLAG_LINEAR == 4
static void (* const gpc_fn[8/*in*/][8/*out*/])
(Pixel *out, const Pixel *in, const Background *back) =
{
/*out: G-8 GA-8 RGB-8 RGBA-8 G-16 GA-16 RGB-16 RGBA-16 */
{gpc_noop,gpc_noop,gpc_noop,gpc_noop, gpc_Lin, gpc_Lin, gpc_Lin, gpc_Lin },
{gpc_bckg,gpc_noop,gpc_bckc,gpc_noop, gpc_preq,gpc_pre, gpc_preq,gpc_pre },
{gpc_g8, gpc_g8, gpc_noop,gpc_noop, gpc_glin,gpc_glin,gpc_lin, gpc_lin },
{gpc_g8b, gpc_g8, gpc_bckc,gpc_noop, gpc_gprq,gpc_gpre,gpc_preq,gpc_pre },
{gpc_sRGB,gpc_sRGB,gpc_sRGB,gpc_sRGB, gpc_noop,gpc_noop,gpc_noop,gpc_noop},
{gpc_b16g,gpc_unpg,gpc_b16c,gpc_unpc, gpc_A, gpc_noop,gpc_A, gpc_noop},
{gpc_sG, gpc_sG, gpc_sRGB,gpc_sRGB, gpc_g16, gpc_g16, gpc_noop,gpc_noop},
{gpc_gb16,gpc_sGp, gpc_cb16,gpc_sCp, gpc_g16, gpc_g16q,gpc_A, gpc_noop}
};
/* The array is repeated for the cases where both the input and output are color
* mapped because then different algorithms are used.
*/
static void (* const gpc_fn_colormapped[8/*in*/][8/*out*/])
(Pixel *out, const Pixel *in, const Background *back) =
{
/*out: G-8 GA-8 RGB-8 RGBA-8 G-16 GA-16 RGB-16 RGBA-16 */
{gpc_noop,gpc_noop,gpc_noop,gpc_noop, gpc_lin, gpc_lin, gpc_lin, gpc_lin },
{gpc_bckg,gpc_noop,gpc_bckc,gpc_noop, gpc_preq,gpc_pre, gpc_preq,gpc_pre },
{gpc_g8, gpc_g8, gpc_noop,gpc_noop, gpc_glin,gpc_glin,gpc_lin, gpc_lin },
{gpc_g8b, gpc_g8, gpc_bckc,gpc_noop, gpc_gprq,gpc_gpre,gpc_preq,gpc_pre },
{gpc_sRGB,gpc_sRGB,gpc_sRGB,gpc_sRGB, gpc_noop,gpc_noop,gpc_noop,gpc_noop},
{gpc_b16g,gpc_unpg,gpc_b16c,gpc_unpc, gpc_A, gpc_noop,gpc_A, gpc_noop},
{gpc_sG, gpc_sG, gpc_sRGB,gpc_sRGB, gpc_g16, gpc_g16, gpc_noop,gpc_noop},
{gpc_gb16,gpc_sGp, gpc_cb16,gpc_sCp, gpc_g16, gpc_g16q,gpc_A, gpc_noop}
};
/* The error arrays record the error in the same matrix; 64 entries, however
* the different algorithms used in libpng for colormap and direct conversions
* mean that four separate matrices are used (for each combination of
* colormapped and direct.)
*
* In some cases the conversion between sRGB formats goes via a linear
* intermediate; an sRGB to linear conversion (as above) is followed by a simple
* linear to sRGB step with no other conversions. This is done by a separate
* error array from an arbitrary 'in' format to one of the four basic outputs
* (since final output is always sRGB not colormapped).
*
* These arrays may be modified if the --accumulate flag is set during the run;
* then instead of logging errors they are simply added in.
*
* The three entries are currently for transparent, partially transparent and
* opaque input pixel values. Notice that alpha should be exact in each case.
*
* Errors in alpha should only occur when converting from a direct format
* to a colormapped format, when alpha is effectively smashed (so large
* errors can occur.) There should be no error in the '0' and 'opaque'
* values. The fourth entry in the array is used for the alpha error (and it
* should always be zero for the 'via linear' case since this is never color
* mapped.)
*
* Mapping to a colormap smashes the colors, it is necessary to have separate
* values for these cases because they are much larger; it is very much
* impossible to obtain a reasonable result, these are held in
* gpc_error_to_colormap.
*/
#if PNG_FORMAT_FLAG_COLORMAP == 8 /* extra check also required */
/* START MACHINE GENERATED */
static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] =
{
{ /* input: sRGB-gray */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: sRGB-gray+alpha */
{ 0, 18, 0, 0 }, { 0, 0, 0, 0 }, { 0, 20, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: sRGB-rgb */
{ 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 893, 0 }, { 0, 0, 893, 0 }, { 0, 0, 811, 0 }, { 0, 0, 811, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: sRGB-rgb+alpha */
{ 0, 4, 13, 0 }, { 0, 14, 13, 0 }, { 0, 19, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 832, 764, 0 }, { 0, 832, 764, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: linear-gray */
{ 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: linear-gray+alpha */
{ 0, 74, 9, 0 }, { 0, 20, 9, 0 }, { 0, 74, 9, 0 }, { 0, 20, 9, 0 },
{ 0, 0, 0, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: linear-rgb */
{ 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
{ 0, 0, 4, 0 }, { 0, 0, 4, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: linear-rgb+alpha */
{ 0, 126, 143, 0 }, { 0, 9, 7, 0 }, { 0, 74, 9, 0 }, { 0, 16, 9, 0 },
{ 0, 4, 4, 0 }, { 0, 5, 4, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: color-mapped-sRGB-gray */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: color-mapped-sRGB-gray+alpha */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: color-mapped-sRGB-rgb */
{ 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 8, 0 }, { 0, 0, 8, 0 },
{ 0, 0, 673, 0 }, { 0, 0, 673, 0 }, { 0, 0, 674, 0 }, { 0, 0, 674, 0 },
{ 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 460, 0 }, { 0, 0, 460, 0 }, { 0, 0, 263, 0 }, { 0, 0, 263, 0 }
}, { /* input: color-mapped-sRGB-rgb+alpha */
{ 0, 6, 8, 0 }, { 0, 7, 8, 0 }, { 0, 75, 8, 0 }, { 0, 9, 8, 0 },
{ 0, 585, 427, 0 }, { 0, 585, 427, 0 }, { 0, 717, 409, 0 }, { 0, 717, 409, 0 },
{ 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 13323, 460, 0 }, { 0, 334, 460, 0 }, { 0, 16480, 263, 0 }, { 0, 243, 263, 0 }
}, { /* input: color-mapped-linear-gray */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: color-mapped-linear-gray+alpha */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 253, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: color-mapped-linear-rgb */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 265, 0 }, { 0, 0, 0, 0 }
}, { /* input: color-mapped-linear-rgb+alpha */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 243, 265, 0 }
}
};
static png_uint_16 gpc_error_via_linear[16][4/*out*/][4] =
{
{ /* input: sRGB-gray */
{ 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 }
}, { /* input: sRGB-gray+alpha */
{ 0, 15, 15, 0 }, { 0, 186, 15, 0 }, { 0, 15, 15, 0 }, { 0, 186, 15, 0 }
}, { /* input: sRGB-rgb */
{ 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 15, 0 }, { 0, 0, 15, 0 }
}, { /* input: sRGB-rgb+alpha */
{ 0, 12, 14, 0 }, { 0, 180, 14, 0 }, { 0, 14, 15, 0 }, { 0, 186, 15, 0 }
}, { /* input: linear-gray */
{ 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }
}, { /* input: linear-gray+alpha */
{ 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }
}, { /* input: linear-rgb */
{ 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }
}, { /* input: linear-rgb+alpha */
{ 0, 1, 1, 0 }, { 0, 8, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }
}, { /* input: color-mapped-sRGB-gray */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: color-mapped-sRGB-gray+alpha */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: color-mapped-sRGB-rgb */
{ 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 14, 0 }, { 0, 0, 14, 0 }
}, { /* input: color-mapped-sRGB-rgb+alpha */
{ 0, 4, 8, 0 }, { 0, 9, 8, 0 }, { 0, 8, 3, 0 }, { 0, 32, 3, 0 }
}, { /* input: color-mapped-linear-gray */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: color-mapped-linear-gray+alpha */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: color-mapped-linear-rgb */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}, { /* input: color-mapped-linear-rgb+alpha */
{ 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
}
};
static png_uint_16 gpc_error_to_colormap[8/*i*/][8/*o*/][4] =
{
{ /* input: sRGB-gray */
{ 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
{ 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 }
}, { /* input: sRGB-gray+alpha */
{ 0, 19, 2, 0 }, { 0, 255, 2, 25 }, { 0, 88, 2, 0 }, { 0, 255, 2, 25 },
{ 0, 1012, 745, 0 }, { 0, 16026, 745, 6425 }, { 0, 1012, 745, 0 }, { 0, 16026, 745, 6425 }
}, { /* input: sRGB-rgb */
{ 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 25, 0 }, { 0, 0, 25, 0 },
{ 0, 0, 937, 0 }, { 0, 0, 937, 0 }, { 0, 0, 13677, 0 }, { 0, 0, 13677, 0 }
}, { /* input: sRGB-rgb+alpha */
{ 0, 63, 77, 0 }, { 0, 255, 19, 25 }, { 0, 220, 25, 0 }, { 0, 255, 25, 67 },
{ 0, 17534, 18491, 0 }, { 0, 15614, 2824, 6425 }, { 0, 14019, 13677, 0 }, { 0, 48573, 13677, 17219 }
}, { /* input: linear-gray */
{ 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 },
{ 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }
}, { /* input: linear-gray+alpha */
{ 0, 74, 74, 0 }, { 0, 255, 74, 25 }, { 0, 97, 74, 0 }, { 0, 255, 74, 25 },
{ 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6552 }, { 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6552 }
}, { /* input: linear-rgb */
{ 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 98, 0 }, { 0, 0, 98, 0 },
{ 0, 0, 18664, 0 }, { 0, 0, 18664, 0 }, { 0, 0, 24998, 0 }, { 0, 0, 24998, 0 }
}, { /* input: linear-rgb+alpha */
{ 0, 181, 196, 0 }, { 0, 255, 61, 25 }, { 206, 187, 98, 0 }, { 0, 255, 98, 67 },
{ 0, 18141, 18137, 0 }, { 0, 17494, 17504, 6553 }, { 0, 24979, 24992, 0 }, { 0, 46509, 24992, 17347 }
}
};
/* END MACHINE GENERATED */
#endif /* COLORMAP flag check */
#endif /* flag checks */
typedef struct
{
/* Basic pixel information: */
Image* in_image; /* Input image */
const Image* out_image; /* Output image */
/* 'background' is the value passed to the gpc_ routines, it may be NULL if
* it should not be used (*this* program has an error if it crashes as a
* result!)
*/
Background background_color;
const Background* background;
/* Precalculated values: */
int in_opaque; /* Value of input alpha that is opaque */
int is_palette; /* Sample values come from the palette */
int accumulate; /* Accumlate component errors (don't log) */
int output_8bit; /* Output is 8 bit (else 16 bit) */
void (*in_gp)(Pixel*, png_const_voidp);
void (*out_gp)(Pixel*, png_const_voidp);
void (*transform)(Pixel *out, const Pixel *in, const Background *back);
/* A function to perform the required transform */
void (*from_linear)(Pixel *out, const Pixel *in, const Background *back);
/* For 'via_linear' transforms the final, from linear, step, else NULL */
png_uint_16 error[4];
/* Three error values for transparent, partially transparent and opaque
* input pixels (in turn).
*/
png_uint_16 *error_ptr;
/* Where these are stored in the static array (for 'accumulate') */
}
Transform;
/* Return a 'transform' as above for the given format conversion. */
static void
transform_from_formats(Transform *result, Image *in_image,
const Image *out_image, png_const_colorp background, int via_linear)
{
png_uint_32 in_format, out_format;
png_uint_32 in_base, out_base;
memset(result, 0, sizeof *result);
/* Store the original images for error messages */
result->in_image = in_image;
result->out_image = out_image;
in_format = in_image->image.format;
out_format = out_image->image.format;
if (in_format & PNG_FORMAT_FLAG_LINEAR)
result->in_opaque = 65535;
else
result->in_opaque = 255;
result->output_8bit = (out_format & PNG_FORMAT_FLAG_LINEAR) == 0;
result->is_palette = 0; /* set by caller if required */
result->accumulate = (in_image->opts & ACCUMULATE) != 0;
/* The loaders (which need the ordering information) */
result->in_gp = get_pixel(in_format);
result->out_gp = get_pixel(out_format);
/* Remove the ordering information: */
in_format &= BASE_FORMATS | PNG_FORMAT_FLAG_COLORMAP;
in_base = in_format & BASE_FORMATS;
out_format &= BASE_FORMATS | PNG_FORMAT_FLAG_COLORMAP;
out_base = out_format & BASE_FORMATS;
if (via_linear)
{
/* Check for an error in this program: */
if (out_format & (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLORMAP))
{
fprintf(stderr, "internal transform via linear error 0x%x->0x%x\n",
in_format, out_format);
exit(1);
}
result->transform = gpc_fn[in_base][out_base | PNG_FORMAT_FLAG_LINEAR];
result->from_linear = gpc_fn[out_base | PNG_FORMAT_FLAG_LINEAR][out_base];
result->error_ptr = gpc_error_via_linear[in_format][out_format];
}
else if (~in_format & out_format & PNG_FORMAT_FLAG_COLORMAP)
{
/* The input is not colormapped but the output is, the errors will
* typically be large (only the grayscale-no-alpha case permits preserving
* even 8-bit values.)
*/
result->transform = gpc_fn[in_base][out_base];
result->from_linear = NULL;
result->error_ptr = gpc_error_to_colormap[in_base][out_base];
}
else
{
/* The caller handles the colormap->pixel value conversion, so the
* transform function just gets a pixel value, however because libpng
* currently contains a different implementation for mapping a colormap if
* both input and output are colormapped we need different conversion
* functions to deal with errors in the libpng implementation.
*/
if (in_format & out_format & PNG_FORMAT_FLAG_COLORMAP)
result->transform = gpc_fn_colormapped[in_base][out_base];
else
result->transform = gpc_fn[in_base][out_base];
result->from_linear = NULL;
result->error_ptr = gpc_error[in_format][out_format];
}
/* Follow the libpng simplified API rules to work out what to pass to the gpc
* routines as a background value, if one is not required pass NULL so that
* this program crashes in the even of a programming error.
*/
result->background = NULL; /* default: not required */
/* Rule 1: background only need be supplied if alpha is to be removed */
if (in_format & ~out_format & PNG_FORMAT_FLAG_ALPHA)
{
/* The input value is 'NULL' to use the background and (otherwise) an sRGB
* background color (to use a solid color). The code above uses a fixed
* byte value, BUFFER_INIT8, for buffer even for 16-bit output. For
* linear (16-bit) output the sRGB background color is ignored; the
* composition is always on the background (so BUFFER_INIT8 * 257), except
* that for the colormap (i.e. linear colormapped output) black is used.
*/
result->background = &result->background_color;
if (out_format & PNG_FORMAT_FLAG_LINEAR || via_linear)
{
if (out_format & PNG_FORMAT_FLAG_COLORMAP)
{
result->background_color.ir =
result->background_color.ig =
result->background_color.ib = 0;
result->background_color.dr =
result->background_color.dg =
result->background_color.db = 0;
}
else
{
result->background_color.ir =
result->background_color.ig =
result->background_color.ib = BUFFER_INIT8 * 257;
result->background_color.dr =
result->background_color.dg =
result->background_color.db = 0;
}
}
else /* sRGB output */
{
if (background != NULL)
{
if (out_format & PNG_FORMAT_FLAG_COLOR)
{
result->background_color.ir = background->red;
result->background_color.ig = background->green;
result->background_color.ib = background->blue;
/* TODO: sometimes libpng uses the power law conversion here, how
* to handle this?
*/
result->background_color.dr = sRGB_to_d[background->red];
result->background_color.dg = sRGB_to_d[background->green];
result->background_color.db = sRGB_to_d[background->blue];
}
else /* grayscale: libpng only looks at 'g' */
{
result->background_color.ir =
result->background_color.ig =
result->background_color.ib = background->green;
/* TODO: sometimes libpng uses the power law conversion here, how
* to handle this?
*/
result->background_color.dr =
result->background_color.dg =
result->background_color.db = sRGB_to_d[background->green];
}
}
else if ((out_format & PNG_FORMAT_FLAG_COLORMAP) == 0)
{
result->background_color.ir =
result->background_color.ig =
result->background_color.ib = BUFFER_INIT8;
/* TODO: sometimes libpng uses the power law conversion here, how
* to handle this?
*/
result->background_color.dr =
result->background_color.dg =
result->background_color.db = sRGB_to_d[BUFFER_INIT8];
}
/* Else the output is colormapped and a background color must be
* provided; if pngstest crashes then that is a bug in this program
* (though libpng should png_error as well.)
*/
else
result->background = NULL;
}
}
if (result->background == NULL)
{
result->background_color.ir =
result->background_color.ig =
result->background_color.ib = -1; /* not used */
result->background_color.dr =
result->background_color.dg =
result->background_color.db = 1E30; /* not used */
}
/* Copy the error values into the Transform: */
result->error[0] = result->error_ptr[0];
result->error[1] = result->error_ptr[1];
result->error[2] = result->error_ptr[2];
result->error[3] = result->error_ptr[3];
}
/* Compare two pixels.
*
* OLD error values:
static int error_to_linear = 811; * by experiment *
static int error_to_linear_grayscale = 424; * by experiment *
static int error_to_sRGB = 6; * by experiment *
static int error_to_sRGB_grayscale = 17; * libpng error by calculation +
2 by experiment *
static int error_in_compose = 2; * by experiment *
static int error_in_premultiply = 1;
*
* The following is *just* the result of a round trip from 8-bit sRGB to linear
* then back to 8-bit sRGB when it is done by libpng. There are two problems:
*
* 1) libpng currently uses a 2.2 power law with no linear segment, this results
* in instability in the low values and even with 16-bit precision sRGB(1) ends
* up mapping to sRGB(0) as a result of rounding in the 16-bit representation.
* This gives an error of 1 in the handling of value 1 only.
*
* 2) libpng currently uses an intermediate 8-bit linear value in gamma
* correction of 8-bit values. This results in many more errors, the worse of
* which is mapping sRGB(14) to sRGB(0).
*
* The general 'error_via_linear' is more complex because of pre-multiplication,
* this compounds the 8-bit errors according to the alpha value of the pixel.
* As a result 256 values are pre-calculated for error_via_linear.
*/
#if 0
static int error_in_libpng_gamma;
static int error_via_linear[256]; /* Indexed by 8-bit alpha */
static void
init_error_via_linear(void)
{
int alpha;
error_via_linear[0] = 255; /* transparent pixel */
for (alpha=1; alpha<=255; ++alpha)
{
/* 16-bit values less than 128.5 get rounded to 8-bit 0 and so the worst
* case error arises with 16-bit 128.5, work out what sRGB
* (non-associated) value generates 128.5; any value less than this is
* going to map to 0, so the worst error is floor(value).
*
* Note that errors are considerably higher (more than a factor of 2)
* because libpng uses a simple power law for sRGB data at present.
*
* Add .1 for arithmetic errors inside libpng.
*/
double v = floor(255*pow(.5/*(128.5 * 255 / 65535)*/ / alpha, 1/2.2)+.1);
error_via_linear[alpha] = (int)v;
}
/* This is actually 14.99, but, despite the closeness to 15, 14 seems to work
* ok in this case.
*/
error_in_libpng_gamma = 14;
}
#endif
static void
print_pixel(char string[64], const Pixel *pixel, png_uint_32 format)
{
switch (format & (PNG_FORMAT_FLAG_ALPHA|PNG_FORMAT_FLAG_COLOR))
{
case 0:
sprintf(string, "%s(%d)", format_names[format], pixel->g);
break;
case PNG_FORMAT_FLAG_ALPHA:
sprintf(string, "%s(%d,%d)", format_names[format], pixel->g,
pixel->a);
break;
case PNG_FORMAT_FLAG_COLOR:
sprintf(string, "%s(%d,%d,%d)", format_names[format],
pixel->r, pixel->g, pixel->b);
break;
case PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA:
sprintf(string, "%s(%d,%d,%d,%d)", format_names[format],
pixel->r, pixel->g, pixel->b, pixel->a);
break;
default:
sprintf(string, "invalid-format");
break;
}
}
static int
logpixel(const Transform *transform, png_uint_32 x, png_uint_32 y,
const Pixel *in, const Pixel *calc, const Pixel *out, const char *reason)
{
const png_uint_32 in_format = transform->in_image->image.format;
const png_uint_32 out_format = transform->out_image->image.format;
png_uint_32 back_format = out_format & ~PNG_FORMAT_FLAG_ALPHA;
const char *via_linear = "";
char pixel_in[64], pixel_calc[64], pixel_out[64], pixel_loc[64];
char background_info[100];
print_pixel(pixel_in, in, in_format);
print_pixel(pixel_calc, calc, out_format);
print_pixel(pixel_out, out, out_format);
if (transform->is_palette)
sprintf(pixel_loc, "palette: %lu", (unsigned long)y);
else
sprintf(pixel_loc, "%lu,%lu", (unsigned long)x, (unsigned long)y);
if (transform->from_linear != NULL)
{
via_linear = " (via linear)";
/* And as a result the *read* format which did any background processing
* was itself linear, so the background color information is also
* linear.
*/
back_format |= PNG_FORMAT_FLAG_LINEAR;
}
if (transform->background != NULL)
{
Pixel back;
char pixel_back[64];
back.r = transform->background->ir;
back.g = transform->background->ig;
back.b = transform->background->ib;
back.a = -1; /* not used */
print_pixel(pixel_back, &back, back_format);
sprintf(background_info, " on background %s", pixel_back);
}
else
background_info[0] = 0;
if (transform->in_image->file_name != transform->out_image->file_name)
{
char error_buffer[512];
sprintf(error_buffer,
"(%s) %s error%s:\n %s%s ->\n %s\n not: %s.\n"
"Use --preserve and examine: ", pixel_loc, reason, via_linear,
pixel_in, background_info, pixel_out, pixel_calc);
return logerror(transform->in_image, transform->in_image->file_name,
error_buffer, transform->out_image->file_name);
}
else
{
char error_buffer[512];
sprintf(error_buffer,
"(%s) %s error%s:\n %s%s ->\n %s\n not: %s.\n"
" The error happened when reading the original file with this format.",
pixel_loc, reason, via_linear, pixel_in, background_info, pixel_out,
pixel_calc);
return logerror(transform->in_image, transform->in_image->file_name,
error_buffer, "");
}
}
static int
cmppixel(Transform *transform, png_const_voidp in, png_const_voidp out,
png_uint_32 x, png_uint_32 y/*or palette index*/)
{
int maxerr;
png_const_charp errmsg;
Pixel pixel_in, pixel_calc, pixel_out;
transform->in_gp(&pixel_in, in);
if (transform->from_linear == NULL)
transform->transform(&pixel_calc, &pixel_in, transform->background);
else
{
transform->transform(&pixel_out, &pixel_in, transform->background);
transform->from_linear(&pixel_calc, &pixel_out, NULL);
}
transform->out_gp(&pixel_out, out);
/* Eliminate the case where the input and output values match exactly. */
if (pixel_calc.a == pixel_out.a && pixel_calc.r == pixel_out.r &&
pixel_calc.g == pixel_out.g && pixel_calc.b == pixel_out.b)
return 1;
/* Eliminate the case where the output pixel is transparent and the output
* is 8-bit - any component values are valid. Don't check the input alpha
* here to also skip the 16-bit small alpha cases.
*/
if (transform->output_8bit && pixel_calc.a == 0 && pixel_out.a == 0)
return 1;
/* Check for alpha errors first; an alpha error can damage the components too
* so avoid spurious checks on components if one is found.
*/
errmsg = NULL;
{
int err_a = abs(pixel_calc.a-pixel_out.a);
if (err_a > transform->error[3])
{
/* If accumulating check the components too */
if (transform->accumulate)
transform->error[3] = (png_uint_16)err_a;
else
errmsg = "alpha";
}
}
/* Now if *either* of the output alphas are 0 but alpha is within tolerance
* eliminate the 8-bit component comparison.
*/
if (errmsg == NULL && transform->output_8bit &&
(pixel_calc.a == 0 || pixel_out.a == 0))
return 1;
if (errmsg == NULL) /* else just signal an alpha error */
{
int err_r = abs(pixel_calc.r - pixel_out.r);
int err_g = abs(pixel_calc.g - pixel_out.g);
int err_b = abs(pixel_calc.b - pixel_out.b);
int limit;
if ((err_r | err_g | err_b) == 0)
return 1; /* exact match */
/* Mismatch on a component, check the input alpha */
if (pixel_in.a >= transform->in_opaque)
{
errmsg = "opaque component";
limit = 2; /* opaque */
}
else if (pixel_in.a > 0)
{
errmsg = "alpha component";
limit = 1; /* partially transparent */
}
else
{
errmsg = "transparent component (background)";
limit = 0; /* transparent */
}
maxerr = err_r;
if (maxerr < err_g) maxerr = err_g;
if (maxerr < err_b) maxerr = err_b;
if (maxerr <= transform->error[limit])
return 1; /* within the error limits */
/* Handle a component mis-match; log it, just return an error code, or
* accumulate it.
*/
if (transform->accumulate)
{
transform->error[limit] = (png_uint_16)maxerr;
return 1; /* to cause the caller to keep going */
}
}
/* Failure to match and not accumulating, so the error must be logged. */
return logpixel(transform, x, y, &pixel_in, &pixel_calc, &pixel_out, errmsg);
}
static png_byte
component_loc(png_byte loc[4], png_uint_32 format)
{
/* Given a format return the number of channels and the location of
* each channel.
*
* The mask 'loc' contains the component offset of the channels in the
* following order. Note that if 'format' is grayscale the entries 1-3 must
* all contain the location of the gray channel.
*
* 0: alpha
* 1: red or gray
* 2: green or gray
* 3: blue or gray
*/
png_byte channels;
if (format & PNG_FORMAT_FLAG_COLOR)
{
channels = 3;
loc[2] = 1;
if (format & PNG_FORMAT_FLAG_BGR)
{
loc[1] = 2;
loc[3] = 0;
}
else
{
loc[1] = 0;
loc[3] = 2;
}
}
else
{
channels = 1;
loc[1] = loc[2] = loc[3] = 0;
}
if (format & PNG_FORMAT_FLAG_ALPHA)
{
if (format & PNG_FORMAT_FLAG_AFIRST)
{
loc[0] = 0;
++loc[1];
++loc[2];
++loc[3];
}
else
loc[0] = channels;
++channels;
}
else
loc[0] = 4; /* not present */
return channels;
}
/* Compare two images, the original 'a', which was written out then read back in
* to * give image 'b'. The formats may have been changed.
*/
static int
compare_two_images(Image *a, Image *b, int via_linear,
png_const_colorp background)
{
ptrdiff_t stridea = a->stride;
ptrdiff_t strideb = b->stride;
png_const_bytep rowa = a->buffer+16;
png_const_bytep rowb = b->buffer+16;
const png_uint_32 width = a->image.width;
const png_uint_32 height = a->image.height;
const png_uint_32 formata = a->image.format;
const png_uint_32 formatb = b->image.format;
const unsigned int a_sample = PNG_IMAGE_SAMPLE_SIZE(formata);
const unsigned int b_sample = PNG_IMAGE_SAMPLE_SIZE(formatb);
int alpha_added, alpha_removed;
int bchannels;
int btoa[4];
png_uint_32 y;
Transform tr;
/* This should never happen: */
if (width != b->image.width || height != b->image.height)
return logerror(a, a->file_name, ": width x height changed: ",
b->file_name);
/* Set up the background and the transform */
transform_from_formats(&tr, a, b, background, via_linear);
/* Find the first row and inter-row space. */
if (!(formata & PNG_FORMAT_FLAG_COLORMAP) &&
(formata & PNG_FORMAT_FLAG_LINEAR))
stridea *= 2;
if (!(formatb & PNG_FORMAT_FLAG_COLORMAP) &&
(formatb & PNG_FORMAT_FLAG_LINEAR))
strideb *= 2;
if (stridea < 0) rowa += (height-1) * (-stridea);
if (strideb < 0) rowb += (height-1) * (-strideb);
/* First shortcut the two colormap case by comparing the image data; if it
* matches then we expect the colormaps to match, although this is not
* absolutely necessary for an image match. If the colormaps fail to match
* then there is a problem in libpng.
*/
if (formata & formatb & PNG_FORMAT_FLAG_COLORMAP)
{
/* Only check colormap entries that actually exist; */
png_const_bytep ppa, ppb;
int match;
png_byte in_use[256], amax = 0, bmax = 0;
memset(in_use, 0, sizeof in_use);
ppa = rowa;
ppb = rowb;
/* Do this the slow way to accumulate the 'in_use' flags, don't break out
* of the loop until the end; this validates the color-mapped data to
* ensure all pixels are valid color-map indexes.
*/
for (y=0, match=1; y<height && match; ++y, ppa += stridea, ppb += strideb)
{
png_uint_32 x;
for (x=0; x<width; ++x)
{
png_byte bval = ppb[x];
png_byte aval = ppa[x];
if (bval > bmax)
bmax = bval;
if (bval != aval)
match = 0;
in_use[aval] = 1;
if (aval > amax)
amax = aval;
}
}
/* If the buffers match then the colormaps must too. */
if (match)
{
/* Do the color-maps match, entry by entry? Only check the 'in_use'
* entries. An error here should be logged as a color-map error.
*/
png_const_bytep a_cmap = (png_const_bytep)a->colormap;
png_const_bytep b_cmap = (png_const_bytep)b->colormap;
int result = 1; /* match by default */
/* This is used in logpixel to get the error message correct. */
tr.is_palette = 1;
for (y=0; y<256; ++y, a_cmap += a_sample, b_cmap += b_sample)
if (in_use[y])
{
/* The colormap entries should be valid, but because libpng doesn't
* do any checking at present the original image may contain invalid
* pixel values. These cause an error here (at present) unless
* accumulating errors in which case the program just ignores them.
*/
if (y >= a->image.colormap_entries)
{
if ((a->opts & ACCUMULATE) == 0)
{
char pindex[9];
sprintf(pindex, "%lu[%lu]", (unsigned long)y,
(unsigned long)a->image.colormap_entries);
logerror(a, a->file_name, ": bad pixel index: ", pindex);
}
result = 0;
}
else if (y >= b->image.colormap_entries)
{
if ((a->opts & ACCUMULATE) == 0)
{
char pindex[9];
sprintf(pindex, "%lu[%lu]", (unsigned long)y,
(unsigned long)b->image.colormap_entries);
logerror(b, b->file_name, ": bad pixel index: ", pindex);
}
result = 0;
}
/* All the mismatches are logged here; there can only be 256! */
else if (!cmppixel(&tr, a_cmap, b_cmap, 0, y))
result = 0;
}
/* If reqested copy the error values back from the Transform. */
if (a->opts & ACCUMULATE)
{
tr.error_ptr[0] = tr.error[0];
tr.error_ptr[1] = tr.error[1];
tr.error_ptr[2] = tr.error[2];
tr.error_ptr[3] = tr.error[3];
result = 1; /* force a continue */
}
return result;
}
/* else the image buffers don't match pixel-wise so compare sample values
* instead, but first validate that the pixel indexes are in range (but
* only if not accumulating, when the error is ignored.)
*/
else if ((a->opts & ACCUMULATE) == 0)
{
/* Check the original image first,
* TODO: deal with input images with bad pixel values?
*/
if (amax >= a->image.colormap_entries)
{
char pindex[9];
sprintf(pindex, "%d[%lu]", amax,
(unsigned long)a->image.colormap_entries);
return logerror(a, a->file_name, ": bad pixel index: ", pindex);
}
else if (bmax >= b->image.colormap_entries)
{
char pindex[9];
sprintf(pindex, "%d[%lu]", bmax,
(unsigned long)b->image.colormap_entries);
return logerror(b, b->file_name, ": bad pixel index: ", pindex);
}
}
}
/* We can directly compare pixel values without the need to use the read
* or transform support (i.e. a memory compare) if:
*
* 1) The bit depth has not changed.
* 2) RGB to grayscale has not been done (the reverse is ok; we just compare
* the three RGB values to the original grayscale.)
* 3) An alpha channel has not been removed from an 8-bit format, or the
* 8-bit alpha value of the pixel was 255 (opaque).
*
* If an alpha channel has been *added* then it must have the relevant opaque
* value (255 or 65535).
*
* The fist two the tests (in the order given above) (using the boolean
* equivalence !a && !b == !(a || b))
*/
if (!(((formata ^ formatb) & PNG_FORMAT_FLAG_LINEAR) |
(formata & (formatb ^ PNG_FORMAT_FLAG_COLOR) & PNG_FORMAT_FLAG_COLOR)))
{
/* Was an alpha channel changed? */
const png_uint_32 alpha_changed = (formata ^ formatb) &
PNG_FORMAT_FLAG_ALPHA;
/* Was an alpha channel removed? (The third test.) If so the direct
* comparison is only possible if the input alpha is opaque.
*/
alpha_removed = (formata & alpha_changed) != 0;
/* Was an alpha channel added? */
alpha_added = (formatb & alpha_changed) != 0;
/* The channels may have been moved between input and output, this finds
* out how, recording the result in the btoa array, which says where in
* 'a' to find each channel of 'b'. If alpha was added then btoa[alpha]
* ends up as 4 (and is not used.)
*/
{
int i;
png_byte aloc[4];
png_byte bloc[4];
/* The following are used only if the formats match, except that
* 'bchannels' is a flag for matching formats. btoa[x] says, for each
* channel in b, where to find the corresponding value in a, for the
* bchannels. achannels may be different for a gray to rgb transform
* (a will be 1 or 2, b will be 3 or 4 channels.)
*/
(void)component_loc(aloc, formata);
bchannels = component_loc(bloc, formatb);
/* Hence the btoa array. */
for (i=0; i<4; ++i) if (bloc[i] < 4)
btoa[bloc[i]] = aloc[i]; /* may be '4' for alpha */
if (alpha_added)
alpha_added = bloc[0]; /* location of alpha channel in image b */
else
alpha_added = 4; /* Won't match an image b channel */
if (alpha_removed)
alpha_removed = aloc[0]; /* location of alpha channel in image a */
else
alpha_removed = 4;
}
}
else
{
/* Direct compare is not possible, cancel out all the corresponding local
* variables.
*/
bchannels = 0;
alpha_removed = alpha_added = 4;
btoa[3] = btoa[2] = btoa[1] = btoa[0] = 4; /* 4 == not present */
}
for (y=0; y<height; ++y, rowa += stridea, rowb += strideb)
{
png_const_bytep ppa, ppb;
png_uint_32 x;
for (x=0, ppa=rowa, ppb=rowb; x<width; ++x)
{
png_const_bytep psa, psb;
if (formata & PNG_FORMAT_FLAG_COLORMAP)
psa = (png_const_bytep)a->colormap + a_sample * *ppa++;
else
psa = ppa, ppa += a_sample;
if (formatb & PNG_FORMAT_FLAG_COLORMAP)
psb = (png_const_bytep)b->colormap + b_sample * *ppb++;
else
psb = ppb, ppb += b_sample;
/* Do the fast test if possible. */
if (bchannels)
{
/* Check each 'b' channel against either the corresponding 'a'
* channel or the opaque alpha value, as appropriate. If
* alpha_removed value is set (not 4) then also do this only if the
* 'a' alpha channel (alpha_removed) is opaque; only relevant for
* the 8-bit case.
*/
if (formatb & PNG_FORMAT_FLAG_LINEAR) /* 16-bit checks */
{
png_const_uint_16p pua = aligncastconst(png_const_uint_16p, psa);
png_const_uint_16p pub = aligncastconst(png_const_uint_16p, psb);
switch (bchannels)
{
case 4:
if (pua[btoa[3]] != pub[3]) break;
case 3:
if (pua[btoa[2]] != pub[2]) break;
case 2:
if (pua[btoa[1]] != pub[1]) break;
case 1:
if (pua[btoa[0]] != pub[0]) break;
if (alpha_added != 4 && pub[alpha_added] != 65535) break;
continue; /* x loop */
default:
break; /* impossible */
}
}
else if (alpha_removed == 4 || psa[alpha_removed] == 255)
{
switch (bchannels)
{
case 4:
if (psa[btoa[3]] != psb[3]) break;
case 3:
if (psa[btoa[2]] != psb[2]) break;
case 2:
if (psa[btoa[1]] != psb[1]) break;
case 1:
if (psa[btoa[0]] != psb[0]) break;
if (alpha_added != 4 && psb[alpha_added] != 255) break;
continue; /* x loop */
default:
break; /* impossible */
}
}
}
/* If we get to here the fast match failed; do the slow match for this
* pixel.
*/
if (!cmppixel(&tr, psa, psb, x, y) && (a->opts & KEEP_GOING) == 0)
return 0; /* error case */
}
}
/* If reqested copy the error values back from the Transform. */
if (a->opts & ACCUMULATE)
{
tr.error_ptr[0] = tr.error[0];
tr.error_ptr[1] = tr.error[1];
tr.error_ptr[2] = tr.error[2];
tr.error_ptr[3] = tr.error[3];
}
return 1;
}
/* Read the file; how the read gets done depends on which of input_file and
* input_memory have been set.
*/
static int
read_file(Image *image, png_uint_32 format, png_const_colorp background)
{
memset(&image->image, 0, sizeof image->image);
image->image.version = PNG_IMAGE_VERSION;
if (image->input_memory != NULL)
{
if (!png_image_begin_read_from_memory(&image->image, image->input_memory,
image->input_memory_size))
return logerror(image, "memory init: ", image->file_name, "");
}
else if (image->input_file != NULL)
{
if (!png_image_begin_read_from_stdio(&image->image, image->input_file))
return logerror(image, "stdio init: ", image->file_name, "");
}
else
{
if (!png_image_begin_read_from_file(&image->image, image->file_name))
return logerror(image, "file init: ", image->file_name, "");
}
/* This must be set after the begin_read call: */
if (image->opts & sRGB_16BIT)
image->image.flags |= PNG_IMAGE_FLAG_16BIT_sRGB;
/* Have an initialized image with all the data we need plus, maybe, an
* allocated file (myfile) or buffer (mybuffer) that need to be freed.
*/
{
int result;
png_uint_32 image_format;
/* Print both original and output formats. */
image_format = image->image.format;
if (image->opts & VERBOSE)
{
printf("%s %lu x %lu %s -> %s", image->file_name,
(unsigned long)image->image.width,
(unsigned long)image->image.height,
format_names[image_format & FORMAT_MASK],
(format & FORMAT_NO_CHANGE) != 0 || image->image.format == format
? "no change" : format_names[format & FORMAT_MASK]);
if (background != NULL)
printf(" background(%d,%d,%d)\n", background->red,
background->green, background->blue);
else
printf("\n");
fflush(stdout);
}
/* 'NO_CHANGE' combined with the color-map flag forces the base format
* flags to be set on read to ensure that the original representation is
* not lost in the pass through a colormap format.
*/
if ((format & FORMAT_NO_CHANGE) != 0)
{
if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0 &&
(image_format & PNG_FORMAT_FLAG_COLORMAP) != 0)
format = (image_format & ~BASE_FORMATS) | (format & BASE_FORMATS);
else
format = image_format;
}
image->image.format = format;
image->stride = PNG_IMAGE_ROW_STRIDE(image->image) + image->stride_extra;
allocbuffer(image);
result = png_image_finish_read(&image->image, background,
image->buffer+16, (png_int_32)image->stride, image->colormap);
checkbuffer(image, image->file_name);
if (result)
return checkopaque(image);
else
return logerror(image, image->file_name, ": image read failed", "");
}
}
/* Reads from a filename, which must be in image->file_name, but uses
* image->opts to choose the method. The file is always read in its native
* format (the one the simplified API suggests).
*/
static int
read_one_file(Image *image)
{
if (!(image->opts & READ_FILE) || (image->opts & USE_STDIO))
{
/* memory or stdio. */
FILE *f = fopen(image->file_name, "rb");
if (f != NULL)
{
if (image->opts & READ_FILE)
image->input_file = f;
else /* memory */
{
if (fseek(f, 0, SEEK_END) == 0)
{
long int cb = ftell(f);
if (cb > 0 && (unsigned long int)cb < (size_t)~(size_t)0)
{
png_bytep b = voidcast(png_bytep, malloc((size_t)cb));
if (b != NULL)
{
rewind(f);
if (fread(b, (size_t)cb, 1, f) == 1)
{
fclose(f);
image->input_memory_size = cb;
image->input_memory = b;
}
else
{
free(b);
return logclose(image, f, image->file_name,
": read failed: ");
}
}
else
return logclose(image, f, image->file_name,
": out of memory: ");
}
else if (cb == 0)
return logclose(image, f, image->file_name,
": zero length: ");
else
return logclose(image, f, image->file_name,
": tell failed: ");
}
else
return logclose(image, f, image->file_name, ": seek failed: ");
}
}
else
return logerror(image, image->file_name, ": open failed: ",
strerror(errno));
}
return read_file(image, FORMAT_NO_CHANGE, NULL);
}
#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
static int
write_one_file(Image *output, Image *image, int convert_to_8bit)
{
if (image->opts & FAST_WRITE)
image->image.flags |= PNG_IMAGE_FLAG_FAST;
if (image->opts & USE_STDIO)
{
FILE *f = tmpfile();
if (f != NULL)
{
if (png_image_write_to_stdio(&image->image, f, convert_to_8bit,
image->buffer+16, (png_int_32)image->stride, image->colormap))
{
if (fflush(f) == 0)
{
rewind(f);
initimage(output, image->opts, "tmpfile", image->stride_extra);
output->input_file = f;
if (!checkopaque(image))
return 0;
}
else
return logclose(image, f, "tmpfile", ": flush: ");
}
else
{
fclose(f);
return logerror(image, "tmpfile", ": write failed", "");
}
}
else
return logerror(image, "tmpfile", ": open: ", strerror(errno));
}
else
{
static int counter = 0;
char name[32];
sprintf(name, "%s%d.png", tmpf, ++counter);
if (png_image_write_to_file(&image->image, name, convert_to_8bit,
image->buffer+16, (png_int_32)image->stride, image->colormap))
{
initimage(output, image->opts, output->tmpfile_name,
image->stride_extra);
/* Afterwards, or freeimage will delete it! */
strcpy(output->tmpfile_name, name);
if (!checkopaque(image))
return 0;
}
else
return logerror(image, name, ": write failed", "");
}
/* 'output' has an initialized temporary image, read this back in and compare
* this against the original: there should be no change since the original
* format was written unmodified unless 'convert_to_8bit' was specified.
* However, if the original image was color-mapped, a simple read will zap
* the linear, color and maybe alpha flags, this will cause spurious failures
* under some circumstances.
*/
if (read_file(output, image->image.format | FORMAT_NO_CHANGE, NULL))
{
png_uint_32 original_format = image->image.format;
if (convert_to_8bit)
original_format &= ~PNG_FORMAT_FLAG_LINEAR;
if ((output->image.format & BASE_FORMATS) !=
(original_format & BASE_FORMATS))
return logerror(image, image->file_name, ": format changed on read: ",
output->file_name);
return compare_two_images(image, output, 0/*via linear*/, NULL);
}
else
return logerror(output, output->tmpfile_name,
": read of new file failed", "");
}
#endif
static int
testimage(Image *image, png_uint_32 opts, format_list *pf)
{
int result;
Image copy;
/* Copy the original data, stealing it from 'image' */
checkopaque(image);
copy = *image;
copy.opts = opts;
copy.buffer = NULL;
copy.bufsize = 0;
copy.allocsize = 0;
image->input_file = NULL;
image->input_memory = NULL;
image->input_memory_size = 0;
image->tmpfile_name[0] = 0;
{
png_uint_32 counter;
Image output;
newimage(&output);
result = 1;
/* Use the low bit of 'counter' to indicate whether or not to do alpha
* removal with a background color or by composting onto the image; this
* step gets skipped if it isn't relevant
*/
for (counter=0; counter<2*FORMAT_COUNT; ++counter)
if (format_isset(pf, counter >> 1))
{
png_uint_32 format = counter >> 1;
png_color background_color;
png_colorp background = NULL;
/* If there is a format change that removes the alpha channel then
* the background is relevant. If the output is 8-bit color-mapped
* then a background color *must* be provided, otherwise there are
* two tests to do - one with a color, the other with NULL. The
* NULL test happens second.
*/
if ((counter & 1) == 0)
{
if ((format & PNG_FORMAT_FLAG_ALPHA) == 0 &&
(image->image.format & PNG_FORMAT_FLAG_ALPHA) != 0)
{
/* Alpha/transparency will be removed, the background is
* relevant: make it a color the first time
*/
random_color(&background_color);
background = &background_color;
/* BUT if the output is to a color-mapped 8-bit format then
* the background must always be a color, so increment 'counter'
* to skip the NULL test.
*/
if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0 &&
(format & PNG_FORMAT_FLAG_LINEAR) == 0)
++counter;
}
/* Otherwise an alpha channel is not being eliminated, just leave
* background NULL and skip the (counter & 1) NULL test.
*/
else
++counter;
}
/* else just use NULL for background */
resetimage(&copy);
copy.opts = opts; /* in case read_file needs to change it */
result = read_file(&copy, format, background);
if (!result)
break;
/* Make sure the file just read matches the original file. */
result = compare_two_images(image, &copy, 0/*via linear*/, background);
if (!result)
break;
# ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
/* Write the *copy* just made to a new file to make sure the write
* side works ok. Check the conversion to sRGB if the copy is
* linear.
*/
output.opts = opts;
result = write_one_file(&output, &copy, 0/*convert to 8bit*/);
if (!result)
break;
/* Validate against the original too; the background is needed here
* as well so that compare_two_images knows what color was used.
*/
result = compare_two_images(image, &output, 0, background);
if (!result)
break;
if ((format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
(format & PNG_FORMAT_FLAG_COLORMAP) == 0)
{
/* 'output' is linear, convert to the corresponding sRGB format.
*/
output.opts = opts;
result = write_one_file(&output, &copy, 1/*convert to 8bit*/);
if (!result)
break;
/* This may involve a conversion via linear; in the ideal world
* this would round-trip correctly, but libpng 1.5.7 is not the
* ideal world so allow a drift (error_via_linear).
*
* 'image' has an alpha channel but 'output' does not then there
* will a strip-alpha-channel operation (because 'output' is
* linear), handle this by composing on black when doing the
* comparison.
*/
result = compare_two_images(image, &output, 1/*via_linear*/,
background);
if (!result)
break;
}
# endif /* PNG_SIMPLIFIED_WRITE_SUPPORTED */
}
freeimage(&output);
}
freeimage(&copy);
return result;
}
static int
test_one_file(const char *file_name, format_list *formats, png_uint_32 opts,
int stride_extra, int log_pass)
{
int result;
Image image;
newimage(&image);
initimage(&image, opts, file_name, stride_extra);
result = read_one_file(&image);
if (result)
result = testimage(&image, opts, formats);
freeimage(&image);
/* Ensure that stderr is flushed into any log file */
fflush(stderr);
if (log_pass)
{
if (result)
printf("PASS:");
else
printf("FAIL:");
# ifndef PNG_SIMPLIFIED_WRITE_SUPPORTED
printf(" (no write)");
# endif
print_opts(opts);
printf(" %s\n", file_name);
/* stdout may not be line-buffered if it is piped to a file, so: */
fflush(stdout);
}
else if (!result)
exit(1);
return result;
}
int
main(int argc, char **argv)
{
png_uint_32 opts = FAST_WRITE;
format_list formats;
const char *touch = NULL;
int log_pass = 0;
int redundant = 0;
int stride_extra = 0;
int retval = 0;
int c;
init_sRGB_to_d();
#if 0
init_error_via_linear();
#endif
format_init(&formats);
for (c=1; c<argc; ++c)
{
const char *arg = argv[c];
if (strcmp(arg, "--log") == 0)
log_pass = 1;
else if (strcmp(arg, "--fresh") == 0)
{
memset(gpc_error, 0, sizeof gpc_error);
memset(gpc_error_via_linear, 0, sizeof gpc_error_via_linear);
}
else if (strcmp(arg, "--file") == 0)
opts |= READ_FILE;
else if (strcmp(arg, "--memory") == 0)
opts &= ~READ_FILE;
else if (strcmp(arg, "--stdio") == 0)
opts |= USE_STDIO;
else if (strcmp(arg, "--name") == 0)
opts &= ~USE_STDIO;
else if (strcmp(arg, "--verbose") == 0)
opts |= VERBOSE;
else if (strcmp(arg, "--quiet") == 0)
opts &= ~VERBOSE;
else if (strcmp(arg, "--preserve") == 0)
opts |= KEEP_TMPFILES;
else if (strcmp(arg, "--nopreserve") == 0)
opts &= ~KEEP_TMPFILES;
else if (strcmp(arg, "--keep-going") == 0)
opts |= KEEP_GOING;
else if (strcmp(arg, "--fast") == 0)
opts |= FAST_WRITE;
else if (strcmp(arg, "--slow") == 0)
opts &= ~FAST_WRITE;
else if (strcmp(arg, "--accumulate") == 0)
opts |= ACCUMULATE;
else if (strcmp(arg, "--redundant") == 0)
redundant = 1;
else if (strcmp(arg, "--stop") == 0)
opts &= ~KEEP_GOING;
else if (strcmp(arg, "--strict") == 0)
opts |= STRICT;
else if (strcmp(arg, "--sRGB-16bit") == 0)
opts |= sRGB_16BIT;
else if (strcmp(arg, "--linear-16bit") == 0)
opts &= ~sRGB_16BIT;
else if (strcmp(arg, "--tmpfile") == 0)
{
if (c+1 < argc)
{
if (strlen(argv[++c]) >= sizeof tmpf)
{
fflush(stdout);
fprintf(stderr, "%s: %s is too long for a temp file prefix\n",
argv[0], argv[c]);
exit(99);
}
/* Safe: checked above */
strcpy(tmpf, argv[c]);
}
else
{
fflush(stdout);
fprintf(stderr, "%s: %s requires a temporary file prefix\n",
argv[0], arg);
exit(99);
}
}
else if (strcmp(arg, "--touch") == 0)
{
if (c+1 < argc)
touch = argv[++c];
else
{
fflush(stdout);
fprintf(stderr, "%s: %s requires a file name argument\n",
argv[0], arg);
exit(99);
}
}
else if (arg[0] == '+')
{
png_uint_32 format = formatof(arg+1);
if (format > FORMAT_COUNT)
exit(99);
format_set(&formats, format);
}
else if (arg[0] == '-' && arg[1] != 0 && (arg[1] != '0' || arg[2] != 0))
{
fflush(stdout);
fprintf(stderr, "%s: unknown option: %s\n", argv[0], arg);
exit(99);
}
else
{
if (format_is_initial(&formats))
format_default(&formats, redundant);
if (arg[0] == '-')
{
const int term = (arg[1] == '0' ? 0 : '\n');
unsigned int ich = 0;
/* Loop reading files, use a static buffer to simplify this and just
* stop if the name gets to long.
*/
static char buffer[4096];
do
{
int ch = getchar();
/* Don't allow '\0' in file names, and terminate with '\n' or,
* for -0, just '\0' (use -print0 to find to make this work!)
*/
if (ch == EOF || ch == term || ch == 0)
{
buffer[ich] = 0;
if (ich > 0 && !test_one_file(buffer, &formats, opts,
stride_extra, log_pass))
retval = 1;
if (ch == EOF)
break;
ich = 0;
--ich; /* so that the increment below sets it to 0 again */
}
else
buffer[ich] = (char)ch;
} while (++ich < sizeof buffer);
if (ich)
{
buffer[32] = 0;
buffer[4095] = 0;
fprintf(stderr, "%s...%s: file name too long\n", buffer,
buffer+(4096-32));
exit(99);
}
}
else if (!test_one_file(arg, &formats, opts, stride_extra, log_pass))
retval = 1;
}
}
if (opts & ACCUMULATE)
{
unsigned int in;
printf("static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] =\n");
printf("{\n");
for (in=0; in<16; ++in)
{
unsigned int out;
printf(" { /* input: %s */\n ", format_names[in]);
for (out=0; out<16; ++out)
{
unsigned int alpha;
printf(" {");
for (alpha=0; alpha<4; ++alpha)
{
printf(" %d", gpc_error[in][out][alpha]);
if (alpha < 3) putchar(',');
}
printf(" }");
if (out < 15)
{
putchar(',');
if (out % 4 == 3) printf("\n ");
}
}
printf("\n }");
if (in < 15)
putchar(',');
else
putchar('\n');
}
printf("};\n");
printf("static png_uint_16 gpc_error_via_linear[16][4/*out*/][4] =\n");
printf("{\n");
for (in=0; in<16; ++in)
{
unsigned int out;
printf(" { /* input: %s */\n ", format_names[in]);
for (out=0; out<4; ++out)
{
unsigned int alpha;
printf(" {");
for (alpha=0; alpha<4; ++alpha)
{
printf(" %d", gpc_error_via_linear[in][out][alpha]);
if (alpha < 3) putchar(',');
}
printf(" }");
if (out < 3)
putchar(',');
}
printf("\n }");
if (in < 15)
putchar(',');
else
putchar('\n');
}
printf("};\n");
printf("static png_uint_16 gpc_error_to_colormap[8/*i*/][8/*o*/][4] =\n");
printf("{\n");
for (in=0; in<8; ++in)
{
unsigned int out;
printf(" { /* input: %s */\n ", format_names[in]);
for (out=0; out<8; ++out)
{
unsigned int alpha;
printf(" {");
for (alpha=0; alpha<4; ++alpha)
{
printf(" %d", gpc_error_to_colormap[in][out][alpha]);
if (alpha < 3) putchar(',');
}
printf(" }");
if (out < 7)
{
putchar(',');
if (out % 4 == 3) printf("\n ");
}
}
printf("\n }");
if (in < 7)
putchar(',');
else
putchar('\n');
}
printf("};\n");
}
if (retval == 0 && touch != NULL)
{
FILE *fsuccess = fopen(touch, "wt");
if (fsuccess != NULL)
{
int error = 0;
fprintf(fsuccess, "PNG simple API tests succeeded\n");
fflush(fsuccess);
error = ferror(fsuccess);
if (fclose(fsuccess) || error)
{
fflush(stdout);
fprintf(stderr, "%s: write failed\n", touch);
exit(99);
}
}
else
{
fflush(stdout);
fprintf(stderr, "%s: open failed\n", touch);
exit(99);
}
}
return retval;
}
#else /* !PNG_SIMPLIFIED_READ_SUPPORTED */
int main(void)
{
fprintf(stderr, "pngstest: no read support in libpng, test skipped\n");
/* So the test is skipped: */
return 77;
}
#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */
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